the amount of complex ionic solution can be determined colorimetrically for various ratios of
[Mn+] to [L]; the total concentration of metal ion and ligand is kept constant. Measurements of
the absorbance at a suitable wavelength will show a maximum when the ratio of ligand to metal
is equal to that in the complex. The method is known as ‘Job’s Method’, after the originator, and
is often referred to as ‘The Method of Continuous Variation’. Measurement may be made at any
wavelength where the complex shows appreciable absorption. A portion of maximum
absorption is preferred.